There are many applications where knowing the surface structure or internal structure of hard tissue is desirable. A typical solution, especially if the hard tissue is underlying soft tissue as is the case in dental care, is to obtain X-Ray CT images of the hard tissue
U.S. Pat. No. 5,562,448 to Mushabac, the disclosure of which is incorporated herein by reference, describes an array of sensors which are slid over one or more teeth, to determine its surface structure. However, the position of the array must be determined for each measurement of the array. This patent also describes a point-by-point digitizing of jaw-bone surface by penetrating overlying soft tissue to the bone with a sharp probe, multiple times, again, requiring position determination for each point digitization. The multiple position determination may cause registration and/or other accuracy problems.
In dental tooth implantation other than by the method of U.S. Pat. No. 5,562,448, it is common practice to peel the soft gum tissue off of the jaw bone, in order to better visualize the jaw bone surface geometry.
While common practice is to determine the drilling direction by feel, it has been suggested to mount a surgical stent (template) on the jaw bone, to guide the drilling. The stent may be manufactured, for example, using CAD/CAM techniques and based on CT images of the jaw.
U.S. Pat. No. 5,163,940 to Bourque, the disclosure of which is incorporated herein by reference describes a measurement device for making a measurement of a joint portion.